Trooper Adam Leonczyk, attached to the Springfield barracks, said the checkpoint ran from 11 p.m. Friday night to approximately 3 a.m. Saturday morning.

Of the seven arrested, one was charged with operating under the influence of drugs and one arrestee faces a third OUI offense.

The checkpoints are held at various locations around the state. While the State Police announce in advance that a checkpoint will be set up in a county area, the exact location is kept confidential, at least until the unit organizes at a specific point.

Leonczyk said a detail of about 12 troopers was at the West Springfield location, along with cruisers and what Leonczyk called , "The BAT Mobile," or Breathalizer Alcohol Testing unit.

The 40-foot-long bus is actually a mini barracks on wheels, complete with Breathalizer stations, booking area and a holding cell. The unit has on-board video surveillance for the checkpoint area, and internal cameras to monitor arrestees.

The State Police estimate that 270 people are arrested across the state each week and charged with impaired operation of a motor vehicle.